The proposed research is directed at achieving deeper understanding of the basis for prolonged NMR relaxations from water in cancer tissue. Studies are planned for the determination of "fixed charge" composition, alkali cation content cellular potentials and water, all of which are known to be interdependent phenomena. Work will be carried out to detail the sequence of changes in the above properties as a cell goes through the process of malignant transformation in vitro. NMR will be used to monitor other nuclei of biological importance and to characterize the malignant change (e.g., K39, P31, N14). Finally, use will be made of pulse-gradient techniques to gain additional insight into the motional freedom of water molecules and the barriers to diffusion within the cancer cell. BIBLIOGRAPHIC REFERENCE: M. Goldsmith, D. Hor, and R. Damadian, Counter-Ion Activity Coefficients in Solutions of Biological Polyelectrolytes, Physiol. Chem. & Phys. 7, 225 (1975).